Ocean acidification refers to the change in the chemistry of seawater caused primarily by the ocean's absorption of carbon dioxide from the atmosphere.

This data portal provides ocean acidification relevant data for diverse user groups, from shellfish growers to scientists to managers to the public. Originally built for the west coast of the United States, the geographic scope of the portal is now expanding to the entire nation with support from U.S. IOOS and NOAA’s Ocean Acidification Program (OAP) and to Canada, through our partnership with the Hakai Institute and others. The data served here come from diverse partners, including NOAA’s Pacific Marine Environmental Laboratory (PMEL) and many academic and industry providers coordinated by through the various U.S. IOOS regional associations. For further information about ocean acidification, follow the national and regional links, represented by the icons below, as well as links to information on sensors from the Alliance for Coastal Technologies and regional acidification networks.

The seawater chemistry changes from ocean acidification affect the ecology and economy of marine communities, and this is projected to grow with time. We can better prepare for potential impacts to marine communities, fisheries, and livelihoods by learning more about how the ocean absorbs carbon dioxide. IOOS is committed to working with a diversity of partners to provide data about ocean acidification conditions.